This invention relates to an electronic musical instrument, more particularly an electronic musical instrument of the type wherein a musical tone having a fixed formant characteristic and corresponding to a plurality of keys operated at a keyboard is digitally formed.
In prior art electronic musical instruments musical tones are formed by a frequency division method, a harmonic synthesizing method or a modulation method. However, where a musical tone having a fixed formant characteristic, for example, a wind instrument tone or a human voice is to be produced with these method, it is necessary to use a complicated and expensive electrical circuit.
To solve these problems, it has been proposed to modify harmonic coefficients corresponding to respective keys for producing a musical tone having a fixed formant characteristic as disclosed in U.S. Pat. No. 3,956,960.
With this system, however, it is necessary to modify the harmonic coefficients to be produced according to the depressed keys. In above patent it has been implemented to eliminate, attenuate or accentuate certain harmonic components to generate approximately a musical tone having an ideal fixed formant characteristic.